INFECTIOUS DISEASES 2Do 



carcass is -aut&psieS' and the- absence of cholera and other diseases 

 is demonstrated-. Gentrifi^gation of the blood is being practiced by 

 some prodiicers, and this should -be fencburaged, as a cleaner product 

 and one that is more easily injeclfed is -produced. 



Clarified_,anti-hog cholera serum is the name applied to a specially 

 prepared serum from hyperimmune swine. This serum is free from 

 blood cells and fibrin and practically free from hemoglobin. A rel- 

 atively smaller dose is required of clarified than of ordinary serum, 

 and abscess formation is less likely to occur by use than with the 

 usual anti-hog cholera serum. 



The blood obtained from hyperimmune swine by either process is 

 preserved by adding a small percentage of phenol or trikresol and 

 properly sealed and placed in, storage at a temperature of about 50 

 degrees Fahrenheit. Before., the serum is;,used it is tested. First, 

 second, and third bleedings from different hyperimmunes, or the blood 

 from different hyperimmunes obtained by slaughteringj are mixed up 

 to quantities of 80,000 cubic centimeters. This amount constitutes a 

 series, and therefore each series is a composite serum. For a test 

 sample a proportionate quantity is taken from each separate quantity 

 that makes up a series. The sample should be obtained immediately 

 after bleeding, thus obviating reopening of the bottles. 



For the test seven healthy, susceptible pigs, weighing from forty- 

 five to ninety pounds each, are selected. These pigs are maintained in 

 special pens. The test is made as follows: Each of the seven pigs 

 is injected with two cubic centimeters of virus and five of them receive 

 twenty cubic centimeters of serum. The two pigs are designated check 

 pigs, and they should show visible symptoms and die of typical cholera 

 within twelve to eighteen days. A temperature record is maintained 

 for twenty days, and from observing this record the virulence of the 

 virus and the potency of the serum can in a measure be determined. 



This test is not absolute, but it is of value as an indicator. The 

 test should be repeated if the following conditions arise. First, if the 

 check pigs should not show any evidence of cholera within ten to 

 fifteen days ; second, if the check pigs or any of the .other five should 

 show a constant high temperature beginning on the second, third or 

 fourth day after the test begins ; third, if either of the five pigs should 

 die of cholera during the time of the test. 



The serum that has been tested and in which the two check pigs 

 have died of cholera and the five pigs have shown no visible illness 

 nor any constant rise of temperature is ready for mixing and bottling, 



